TRI-SERVICE ELECTRICAL WORKING GROUP (TSEWG) 03/05/09 TSEWG TP-13: UFC 3-501-03N LOAD DEMAND ANALYSES Recent development of UFC 3-500-10, Design: Electrical Engineering, and UFC 3-520-01, Design: Interior Electrical Systems, will result in the cancellation of UFC 3-501-03N, Electrical Engineering Preliminary Considerations. UFC 3-501-03N contains in its entirety MIL-HDBK 1004/1, Electrical Engineering Preliminary Design Considerations. This Technical Paper has been developed to retain the load demand analysis information originally contained in MIL-HDBK 1004/1. 1 MIL-HDBK-1004/1 30 MAY 1988 SUPERSEDING DM-4.1 MARCH 1983 MILITARY HANDBOOK ELECTRICAL ENGINEERING PRELIMINARY DESIGN CONSIDERATIONS AMSC N/A DISTRIBUTION STATEMENT A. APPROVED FOR PUBLIC RELEASE: DISTRIBUTION IS UNLIMITED AREA FACR Section 1: PRELIMINARY DATA 1.1 Scope. This handbook provides the criteria necessary for the proper selection of electric power sources and distribution systems. It covers preliminary load estimating factors, electrical power sources, and distribution systems. 1.2 Cancellation. This handbook cancels and supersedes DM-4.1, Electrical Engineering Preliminary Design Considerations, of December l979, and change dated 1 March 1983. 1.3 Load Data. Before specific electric power sources and distribution systems can be considered, realistic preliminary load data must be compiled. The expected electric power demand on intermediate substations, and on the main electric power supply, shall be calculated from the connected load layout by applying appropriate factors. Determine these factors by load analysis and by combining loads progressively. To combine the loads, start at the ends of the smallest feeders and work back to the electric power source. Because all loads must be on a common kilowatt (kW) or kilovolt- ampere (kVA) basis, it is necessary to convert motor horsepower ratings to input kilowatts or kilovolt-amperes before combining them with other loads already expressed in those terms. Preliminary electric power load estimates can be made by using the approximate value of one kilovolt-ampere of input per horsepower (hp) at full load. Preliminary estimates of lighting loads may be made by assuming watts per ftÀ2Ù (mÀ2Ù) of building area. 1.4 Load Analysis. To determine appropriate load estimating factors, using the tables and factors in this manual as guides analyze the characteristics of each load. Consider items such as environmental conditions of weather, geographical location, and working hours, as the situation dictates. Notice that when the load densities in w/ftÀ2Ù (mÀ2Ù) are used only in preliminary estimates, the demand and load factors will be used in the final designs. 1.5 Terminology. Five terms are essential to the analysis of load characteristics: demand factor, coincidence factor, diversity factor, and maximum demand. These terms are defined in paras. 1.5.1 through 1.5.4. 1.5.1 Demand Factor. The demand factor is the ratio of the maximum demand on a system to the total connected load of the system or EQUATION: Demand factor = Maximum demand load (1) ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Total load connected 1.5.2 Coincidence Factor. The coincidence factor is the ratio of the maximum demand of a system, or part under consideration, to the sum of the individual maximum demands of the subdivisions or EQUATION: Coincidence factor = Maximum system demand (2) ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Sum of individual maximum demands 1 1.5.3 Diversity Factor. The diversity factor is the reciprocal of the coincidence factor or EQUATION: Diversity factor = Sum of individual maximum demands (3) ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Maximum system demand 1.5.4 Load Factor. The load factor is the ratio of the average load over a designated period of time, usually 1 year, to the maximum load occurring in that period or EQUATION: Load factor = Average load (4) ÄÄÄÄÄÄÄÄÄÄÄÄ Maximum load 1.5.5 Maximum Demand. The maximum demand is the integrated demand for a specified time interval, i.e., 5 minutes, 15 minutes, 30 minutes, or other appropriate time intervals, rather than the instantaneous or peak demand. 2 Section 2: ESTIMATION OF LOADS 2.1 Preparation of Load Data. Load data are generally computed in steps such as: a) individual loads, b) area loads, and c) activity loads. A particular design problem may be limited to step a), to steps a) and b), or may encompass steps a), b), and c). This section outlines each step as a separate entity, dependent only on previous steps for data. Paragraphs 2.2 through 2.4.4 describe the three loads. 2.2 Individual Loads. Individual loads are those with one incoming service supplying utilization voltage to the premises. In general, these loads would comprise single structures. Large structures could contain more than one function; for example, aircraft operations, aircraft fire and rescue stations, and photographic buildings. Under this condition, factors that have been developed and keyed to Navy category codes (refer to Table 1) would be used. In this case, the factors listed under Navy Category Code 141-40, 141-20, and 141-60, respectively, would be combined to obtain the total load. 2.2.1 Lighting. To eliminate lighting loads, divide a facility area into its significant components by function (for example, office, storage, mechanical, and corridor). Determine the average lighting level and type of light source for each area. Consider requirements for supplementary lighting (for example, floodlighting, security lighting, and special task lighting). Preliminary load estimates may be made based on the following load allowances: a) 1 W/ftÀ2Ù (10.76W/mÀ2Ù) for each 6 to 8 fc (60 to 80 dekalux) of incandescent illumination. b) 1 W/ftÀ2Ù for each 15 to 20 fc (150 to 200 dekalux) of fluorescent illumination. c) 1 W/ftÀ2Ù for each 12 to l8 fc (120 to l80 dekalux) of mercury vapor illumination. d) 1 W/ftÀ2Ù for each 26 to 36 fc (260 to 360 dekalux) of metal halide illumination. e) 1 W/ftÀ2Ù for each 33 to 54 fc (330 to 540 dekalux) of high pressure sodium illumination. 2.2.1.1 Small Appliance Loads. Small appliance loads shall include those served by general purpose receptacles. In general, the dividing of areas by function for estimating lighting loads will serve for estimating small appliance loads. The determination of loads requires not only a knowledge of the function of an area, but to what extent its occupants use small appliances. For example, an office area demand may average about 1 W/ftÀ2Ù 3 Table 1 Factors for Individual Facilities by Navy Category Code (See Note 1) ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ DEMAND LOAD NAVY FACTOR FACTOR CODE DESCRIPTION (%) (%) ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ 100 Operational and Training Facilities: 121 Aircraft fueling/dispensing facility . .40-60 16-20 122 Marine fuel dispensing . .40-60 16-20 123 10 Filling station . .40-60 13-17 125 16 Miscellaneous POL pipeline facilities . .100 13-17 126 Liquid fueling and dispensing-other . .40-60 3- 7 131 Communications - buildings . .60-65 70-75 131 40 Telephone exchange building . .55-70 20-25 133 75 Air surveillance radar building . .55-70 70-75 137 40 Port control office . .55-70 20-25 141 11 Air passenger terminal building . .65-80 28-32 141 20 Aircraft fire and rescue station . .25-35 13-17 141 30 Aircraft line operations building . .65-80 24-28 141 40 Aircraft operations building *EXC 141-70* . .65-80 28-32 141 60 Photographic building . .65-80 16-20 171 10 Academic instruction building . .40-60 22-26 171 20 Applied instruction building . .35-65 24-28 171 40 Drill Hall . .75-85 3- 7 200 Maintenance and Production Facilities: 211 05 Maintenance Hangar O/H space (high bay) . .45-50 28-30 211 06 Maintenance Hangar - 01 space (crew equipment). .45-50 28-30 211 07 Maintenance Hangar - 02 space (administrative) . .45-50 28-30 211 10 Aircraft overhaul and repair shop (NARF) . .32-38 25-30 211 12 Paint/finishing hangar . .65-75 25-27 211 20 Engine overhaul shop (NARF) . .32-38 20-25 211 30 Aircraft/engine accessories overhaul shop (NAR) . .32-38 25-30 211 75 Parachute/survival equipment . .60-65 23-28 211 81 Engine test cell (Non-NARF) . .42-48 25-30 211 96 Maintenance, aircraft spares storage (MISC) . .58-63 23-28 212 20 Missile equipment maintenance ship . .35-40 15-20 213 10 Drydock . .5-10 0.5-1 214-10 Combat vehicle maintenance shop . .55-65 20-25 214-20 Automobile vehicle maintenance - noncombat . .55-65 20-25 215 Maintenance - weapons / spares . .70-80 20-25 216 10 Ammunition rework and overhaul shop . .35-40 18-22 216 20 Rocket rework and overhaul shop . .35-40 18-22 216 30 Mines and depth charge rework shop . .35-40 15-20 216 40 Torpedo shop . .45-55 18-22 216 50 Special weapons shop . .35-40 18-22 216 60 Quality evaluation laboratory . .55-65 22-27 Note 1: Demand factors include allowance for system loss. 4 Table 1 (Continued) Factors for Individual Facilities by Navy Category Code[1] ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ DEMAND LOAD NAVY FACTOR FACTOR CODE DESCRIPTION (%) (%) ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ 217 10 Electronics/communications maintenance shop . .35-40 20-25 218 20 Construction/weight handling equipment shop . .35-45 20-25 218 40 Railroad equipment shop . .35-45 15-20 218 50 Battery shop . .55-65 20-25 219 10 Public works shop . .32-38 18-22 221 10 Aircraft engine assembly plant . .32-38 20-25 222 10 Missile assembly buildings . .35-40 15-20 222 20 Missile handling launch equipment . .35-40 15-20 223 10 Fabrication/assembly building . .22-27 24-29 225 10 Small arms plant . .15-20 22-27 225 20 Light gun (20mm/51n) plant . .15-20 22-27 225 30 Heavy gun (6/161n) plant . .16-21 21-26 225 50 Launcher/projector plant .